Our model for the primary mass distributions for 1G+2G  and 2G+2G  mergers is built on the premise that 2G+2G  black holes are roughly twice as massive as 1G+1G  black holes.While mass energy is radiated away in GWs so that the remnant mass is a few percent less than the sum of the primary and secondary masses [1]}, [2]}, [3]}, this is negligible compared to astrophysical modeling uncertainties.
We make the simplifying assumption that in a 1G+2G  binary, the primary is always the 2G  black hole [4]}.
Thus, the 1G+2G  and 2G+2G  primary mass spectra are modeled as
\(\pi (m_1|\Lambda , \textsf {1G+2G} {}) \propto & {}\: \pi \left(\frac{m_1}{2}|\Lambda , \textsf {1G+1G} {}\right), \\\pi (m_1|\Lambda , \textsf {2G+2G} {}) \propto & {}\: \pi \left(\frac{m_1}{2}|\Lambda , \textsf {1G+1G} {}\right),\) 
